HIGH STRENGTH STEEL WELD METAL FOR DEMANDING STRUCTURAL APPLICATIONS

摘要

Weld metals and methods for welding ferritic steels are provided. The weld metals have high strength and high ductile tearing resistance and are suitable for use in strain based pipelines. The weld metals are comprised of between 0.03 and 0.08 wt.% carbon, between 2.0 and 3.5 wt.% nickel, not greater than about 2.0 wt.% manganese, not greater than about 0.80 wt.% molybdenum, not greater than about 0.70 wt.% silicon, not greater than about 0.03 wt.% aluminum, not greater than 0.02 wt.% titanium, not greater than 0.04 wt.% zirconium, between 100 and 225 ppm oxygen, not greater than about 100 ppm nitrogen, not greater than about 100 ppm sulfur, not greater than about 100 ppm phosphorus, and the balance iron. The weld metals are applied using a power source with pulsed current waveform control with 5% CO₂ and 2% oxygen in the shielding gas.